JP5620338B2 - Power tools - Google Patents

Description

  The present invention relates to a power tool such as a disk grinder, a screw tightening tool, or an electric drill for drilling which is equipped with an electric motor as a drive source.

This type of power tool generally includes a reduction gear train for decelerating (shifting) the output rotational speed of the drive motor and a gear train for changing the output direction.
In addition to the power tools, the drive motor transmission mechanism includes a continuously variable transmission mechanism (CVT) that continuously changes the reduction ratio in addition to the gear train as described above. It is publicly known. Conventionally, a continuously variable transmission mechanism using a so-called traction drive mechanism has been known. The following patent document discloses a technique related to an electric tool having a traction drive type continuously variable transmission mechanism.
The traction drive type continuously variable transmission mechanism presses a sun roller rotated by a drive motor against a plurality of conical planetary rollers supported by a holder, and rotates the planetary roller using the rolling contact obtained thereby. However, the holder is revolved around the output shaft to transmit the rotational force. Each planetary roller is in pressure contact with the inner peripheral side of the annular transmission ring. By displacing the speed change ring in the axial direction, the pressure contact position of the speed change ring with respect to the conical surface of the planetary roller is displaced between the small diameter side and the large diameter side to change the pressure contact diameter, thereby reducing the output rotation speed. It is possible to shift in stages.
The transmission ring is provided so as to be capable of being displaced in the axial direction in a state where displacement and elastic deformation in the direction perpendicular to the axis are allowed within a certain range. By allowing displacement of the transmission ring in the direction perpendicular to the axis (displacement that produces a radial component, the same applies hereinafter) and elastic deformation, the centering function of the continuously variable transmission mechanism (processing errors, assembly errors, etc. of each component) By allowing the misalignment due to the accumulation of the above, the apparent centering function) is provided, and thereby the pressure contact force with respect to each planetary roller of the transmission ring is made uniform.

Japanese Unexamined Patent Publication No. 6-19740 JP 2002-59370 A Japanese Patent Publication No. 3-73411

However, in the conventional continuously variable transmission mechanism, since the transmission ring is supported so as to be displaceable not only in the axial direction but also in the direction perpendicular to the axial direction, the centering function is provided. It is necessary to secure a space for arranging a member or the like for displacing support in a direction perpendicular to the axis, and as a result, the power tool or the like having the continuously variable transmission mechanism is mainly increased in the radial direction of the transmission ring. There was a problem.
It is an object of the present invention to reduce the size of the power tool mainly in the radial direction of the transmission ring by omitting the alignment function by making the transmission ring movable only in the axial direction.

The above problems are solved by the following invention.
A first aspect of the present invention is a power tool having a continuously variable transmission mechanism that outputs a rotation output of a drive motor steplessly and outputs it to a spindle to which a tip tool is attached. A rotating sun roller, a plurality of conical planetary rollers supported around the holder, a transmission ring inscribed with the conical surfaces of the plurality of planetary rollers, and a plurality of planetary rollers pressed against the sun roller and the transmission ring A thrust generator that transmits rotational force to the spindle while generating thrust is provided, and the transmission ring is moved in the axial direction to change the pressure contact position of the transmission ring against the conical surface of the planetary roller between the small diameter side and the large diameter side. Therefore, the rotation output of the drive motor is steplessly shifted and output to the spindle through the thrust generation unit. The thrust generation unit can be displaced in the direction perpendicular to the axis of the transmission ring and can rotate. A force able to transmit provided by centering function is a power tool having in place of the control ring.
According to the first aspect of the invention, the thrust generating portion is provided not in the conventional transmission ring but in the centering function for allowing misalignment between the members constituting the continuously variable transmission mechanism. For this reason, it is sufficient to support the transmission ring so as to be movable only in the axial direction, and it is not necessary to support the transmission ring so that it can be displaced in the direction perpendicular to the axis as in the prior art. Space for the arrangement can be omitted, and thereby the size of the power tool in the radial direction of the transmission ring can be reduced.
In a second aspect based on the first aspect, the thrust generating portion is divided into two on the upstream side and the downstream side of the rotational force transmission path, and the upstream side is displaced in the direction perpendicular to the axis of the transmission ring with respect to the downstream side. It is a power tool provided.
According to the second aspect of the present invention, the upstream side of the torque transmission path is displaced in the direction perpendicular to the axis of the transmission ring with respect to the downstream side in the thrust generating section, so that the adjustment between the members constituting the continuously variable transmission mechanism is achieved. A heart is made.
In a third aspect based on the second aspect, the thrust generating portion is provided with a centering hole on one of the upstream side and the downstream side of the rotational force transmission path, a centering shaft is provided on the other side, and the centering shaft is aligned. The power tool is configured to be inserted into a hole so as to be able to transmit a rotational force and to be aligned by displacing the upstream side with respect to the downstream side in the direction perpendicular to the axis of the transmission ring.
According to the third aspect of the present invention, the upstream side of the thrust generating portion changes in the direction perpendicular to the transmission ring shaft with respect to the downstream side within the range in which the alignment shaft can be displaced within the alignment hole. The alignment is made. In a state where the alignment shaft is in contact with the edge of the alignment hole, the upstream side and the downstream side of the rotational force transmission path are coupled for power transmission, and the upstream rotational force is transmitted to the downstream side (spindle side).
A fourth invention is a power tool according to the third invention, wherein an elastic member is interposed between the aligning hole and the aligning shaft to center both of them.
According to the fourth aspect of the invention, the alignment shaft is centered with respect to the alignment hole, and the centering is performed between the upstream side and the downstream side of the thrust generation unit, thereby improving the assembling property of the thrust generation unit. Can be increased.
In a fifth aspect of the present invention based on any one of the first to fourth aspects, the continuously variable transmission mechanism includes a three-point pressure contact structure in which a pressure roller is pressed against a planetary roller in addition to a sun roller and a speed change ring, The power tool is configured such that the generating portion includes a pressing roller that can be displaced in a direction perpendicular to the axis of the transmission ring.
According to the fifth aspect of the present invention, the pressing roller, which is upstream of the rotational force transmission path and is in pressure contact with the planetary roller, is supported by the thrust generating portion so as to be displaceable in the direction perpendicular to the axis of the transmission ring. The alignment is made.

In a sixth aspect based on any one of the first to fifth aspects, the thrust generator is fixed to the spindle in the axial direction and the rotational direction, and the spindle is displaced in the axial direction and the rotational direction. It has a configuration in which a compression spring is interposed between the thrust plate supported so as to be able to generate a pressure contact force between the sun roller and the transmission ring against a plurality of planetary rollers by the urging force of the compression spring, and it rotates with respect to the spindle. This is a power tool configured to transmit force.
According to the sixth aspect, the sun roller and the transmission ring are pressed against the planetary roller by the urging force of the compression spring, and the rotational force is transmitted.
In a seventh aspect based on the sixth aspect, the thrust plate is axially separated from the fixed plate when a relative displacement in the rotational direction due to torque occurs between the fixed plate and the thrust plate. This is a power tool with a cam mechanism for displacement.
According to the seventh invention, when the rotational force is transmitted between the thrust plate on the upstream side of the rotational force transmission path and the fixed plate on the downstream side, a part of the rotational force is transmitted via the cam mechanism. Is added as an external force in the axial direction to the thrust plate, and this is added as a pressing force for pressing the sun roller and the transmission ring against the planetary roller in addition to the pressing force by the urging force of the compression spring. A large pressure contact force of the thrust generating part can be obtained.
An eighth invention is the invention according to any one of the first to seventh inventions, wherein the transmission ring is an inner ring holder provided so as to be movable only in the axial direction of the spindle relative to the housing of the power tool. It is a power tool fixed along the circumference.
According to the eighth aspect, the support structure of the transmission ring can be simplified to reduce the diameter of the housing.
According to a ninth invention, in the eighth invention, the ring holder is supported on the inner peripheral side of an operation ring that is provided so as to be rotatable around the spindle axis relative to the housing, and is operated by rotating the operation ring. In this power tool, the ring holder is displaced in the axial direction to change the pressure contact position with respect to the conical surfaces of the plurality of planetary rollers of the transmission ring between the small diameter side and the large diameter side.
According to the ninth aspect of the present invention, the speed change ring can be displaced in the spindle axial direction by rotating the operation ring, thereby changing the pressure contact position of the speed change ring with respect to the planetary roller and steplessly rotating the drive motor. The gear can be shifted and output to the spindle.

It is a longitudinal section of the whole power tool concerning the embodiment of the present invention. In this embodiment, a rechargeable driver drill is illustrated as an example of a power tool. It is an enlarged view of a continuously variable transmission mechanism. It is an enlarged view of a continuously variable transmission mechanism. The cross-sectional position is different from FIG. FIG. 4 is a view taken in the direction of arrows (IV)-(IV) in FIG. 3, and is a longitudinal sectional view of a thrust generator. FIG. 4 is a side view taken along line (V)-(V) of FIG. 3 and is a side view of the thrust plate. FIG. 6 is a sectional view taken along line (VI)-(VI) in FIG. 5 and is a developed sectional view of a cam groove.

Next, an embodiment of the present invention will be described with reference to FIGS. In the embodiment described below, a rechargeable drill driver is illustrated as an example of the power tool 1. The power tool 1 includes a generally cylindrical tool body 2, a handle 3 provided in a state of projecting sideways from the side of the tool body 2, and a battery pack 4 attached to the tip of the handle 3. It has.
The tool body 2 includes a cylindrical body housing 5 that includes a drive motor 6, a continuously variable transmission mechanism 7, a gear transmission mechanism 8, and a spindle 9 from the rear side. The tip of the spindle 9 is equipped with a chuck 10 for attaching a tip blade. The rotation output of the drive motor 6 is steplessly shifted by the continuously variable transmission mechanism 7 and further decelerated at a constant reduction ratio by the gear transmission mechanism 8 and output to the spindle 9.
A trigger-type switch lever 11 that is pulled by the fingertip of the hand held by the user is disposed near the base of the handle portion 3. When the switch lever 11 is pulled, the drive motor 6 is activated and the spindle 9 rotates. The drive motor 6 is activated using the battery pack 4 as a power source. The battery pack 4 can be repeatedly used by removing it from the tip of the handle portion 3 and charging it with a separately prepared charger.
The power tool 1 of the present embodiment is characterized by the continuously variable transmission mechanism 7 of the tool body 2. A known planetary gear train is used for the gear transmission mechanism 8 disposed on the downstream side of the continuously variable transmission mechanism 7 with respect to the rotational force transmission path. Details of the continuously variable transmission mechanism 7 are shown in FIGS.

The continuously variable transmission mechanism 7 is a three-point pressure contact type traction drive mechanism, and a plurality (six in this embodiment) of planetary rollers 20 to 20 having a conical circumferential surface (conical surface 20a), and the planetary rollers. A sun roller 21, a pressure roller 22, and a transmission ring 26 are provided in pressure contact with 20 to 20, respectively. The six planetary rollers 20 to 20 are rotatably supported at six peripheral positions around the holder 24.
The sun roller 21 is attached to the output shaft 6a of the drive motor 6 and rotates integrally. The sun roller 21 is rotatably supported by the main body housing 5 via a bearing 28. The sun roller 21 is pressed against the neck of each planetary roller 20.
The pressing roller 22 constitutes a thrust generating unit 25, and is pressed against the neck of each planetary roller 20 on the side opposite to the sun roller 21 in the axial direction (on the side opposite to the rotational force transmission direction, right side in FIG. 2). Details of the thrust generator 25 will be described later.
The planetary rollers 20 to 20 are inscribed in an annular transmission ring 26. The conical surface 20 a of each planetary roller 20 is pressed against the inner peripheral surface of the transmission ring 26. The transmission ring 26 is fixed along the inner surface of a ring holder 27 that is supported to be displaceable within a certain range in the axial direction with respect to the main body housing 5. The transmission ring 26 is supported so as to be displaceable only in the axial direction of the intermediate shaft 30 (spindle 9), and is supported so as not to be displaceable in the direction perpendicular to the axis, unlike the prior art. For this reason, the transmission ring 26 does not have a centering function between the constituent members such as the revolution centers of the planetary rollers 20 to 20, and this is different from the conventional one.
Due to the axial movement of the ring holder 27, the transmission ring 26 moves in the spindle axial direction (left and right in FIG. 2), and the pressure contact position of each planetary roller 20 with respect to the conical surface 20a is between the small diameter side and the large diameter side. Due to the displacement, the gear ratio of the continuously variable transmission mechanism 7 changes steplessly. The rotation direction of the pressing roller 22 by the rotation of each planetary roller 20 accompanying the rotation of the sun roller 21 and the revolving direction of the planetary rollers 20 to 20 by the pressure contact state of each planetary roller 20 with respect to the transmission ring 26 (the rotation of the pressing roller 22). Direction) is opposite, and when the transmission ring 26 is displaced to the small diameter side with respect to each planetary roller 20, the revolution speed of the planetary rollers 20 to 20 decreases, and as a result, the rotation speed of the pressure roller 22 increases and becomes intermediate. The shaft 30 rotates at high speed (small reduction ratio). Conversely, when the transmission ring 26 is displaced to the larger diameter side with respect to each planetary roller 20, the revolution speed of the planetary rollers 20 to 20 is increased. As a result, the rotation speed of the pressing roller 22 is reduced and the intermediate shaft 30 rotates at a low speed. (Large reduction ratio). In this way, the intermediate shaft 30 is shifted steplessly by changing the pressure contact position of the transmission ring 26 with respect to each planetary roller 20, and then a rotational force is output to the spindle 9 via the gear transmission mechanism 8.

The rear side of the intermediate shaft 30 is rotatably supported via a bearing 29 attached to the sun roller 21. The sun roller 21 and the intermediate shaft 30 are arranged coaxially with the output shaft 6 a of the drive motor 6. A front side of the intermediate shaft 30 is rotatably supported by the main body housing 5 via a bearing 31. On this intermediate shaft 30, the thrust generating part 25 is supported. A boss portion 22 a is provided on the rear surface of the pressing roller 22 that constitutes the thrust generating portion 25. A holder 24 is supported on the boss 22a so as to be relatively rotatable.
A gear portion 30 a is formed at the front portion of the intermediate shaft 30. The gear portion 30 a functions as a sun gear of the gear transmission mechanism 8. Three planetary gears 8a to 8a are meshed with the gear portion 30a. The three planetary gears 8a to 8a are rotatably supported by the carrier 8b. The three planetary gears 8a to 8a are meshed with the internal gear 8c in an inscribed state. The rear end portion of the spindle 9 is coupled to the carrier 8b. The spindle 9 is rotatably supported by the main body housing 5 via bearings 12 and 13. This spindle 9 is also arranged coaxially with the output shaft 6 a of the drive motor 6 as with the intermediate shaft 30. The rotational force of the intermediate shaft 30 is decelerated at a constant reduction ratio by the gear speed change mechanism 8 constituting the planetary gear train and is output to the spindle 9.

Each pressure contact state of the sun roller 21, the pressure roller 22, and the transmission ring 26 with respect to the planetary rollers 20 to 20 is realized by a pressure contact force (thrust) generated by the thrust generation unit 25. The thrust generating unit 25 includes the above-described pressing roller 22, a fixed plate 32, a thrust plate 33, and a compression spring 34. The fixed plate 32 is fixed on the intermediate shaft 30 so as not to be axially displaceable and rotatable about the axis. A thrust plate 33 is disposed behind the fixed plate 32 (upstream with respect to the direction of transmission of rotational force). The thrust plate 33 is supported on the intermediate shaft 30 so as to be axially displaceable and relatively rotatable about the axis. A compression spring 34 is interposed between the thrust plate 33 and the fixed plate 32. The thrust plate 33 is in contact with the front surface of the pressing roller 22 in an overlapped state. The thrust plate 33 is pressed against the pressing roller 22 by the urging force of the compression spring 34. The pressing roller 22 is pressed against the planetary rollers 20 to 20 by a biasing force of a compression spring 34 added via a thrust plate 33. When the pressing roller 22 is pressed against the planetary rollers 20 to 20 by the urging force of the compression spring 34, the pressing force of the sun roller 21 and the transmission ring 26 against the planetary rollers 20 is generated. Due to the frictional force generated by this pressure contact state, the rotational force of the drive motor 6 is transmitted to the planetary rollers 20 to 20 through the sun roller 21, and thereby the rotation and revolution of each planetary roller 20 (rotation of the holder 24). A rotational force is transmitted to the thrust generating unit 25 through the pressing roller 22, and this is transmitted to the intermediate shaft 30 through the fixed plate 32.
The holder 24 is rotatably supported with respect to the boss portion 22a. The support hole 22c of the boss portion 22a is set to have an inner diameter (clearance) that allows the pressing roller 22 to be displaced in the radial direction with respect to the intermediate shaft 30 in a slight range. Since the pressing roller 22 is displaceable in the radial direction with respect to the intermediate shaft 30, centering (alignment) of the revolution center of the planetary rollers 20 to 20 with respect to the transmission ring 26 and the like is performed. As described above, in this embodiment, the thrust generating unit 25 replaces the conventional transmission ring to align the constituent members such as the alignment of the planetary rollers 20 to 20 with respect to the transmission ring 26. .

A device is provided between the pressing roller 22 and the thrust plate 33 to integrate the rotation of the intermediate shaft 30 about the axis while allowing the radial displacement of the pressing roller 22 within a certain range. As shown in FIGS. 3 and 4, four alignment shafts 35 to 35 are attached to the thrust plate 33. The four alignment shafts 35 to 35 are fixed so as to protrude rearward (left side in FIG. 3) from the rear surface of the thrust plate 33. Moreover, as shown in FIG. 4, the four alignment shafts 35-35 are arrange | positioned in the position of 4 equally on the same periphery.
The four alignment shafts 35 to 35 enter the alignment holes 22b provided in the pressing roller 22, respectively. The four alignment holes 22 b to 22 b are each formed with an inner diameter (clearance) sufficiently larger than the diameter of the alignment shaft 35. The clearance between the alignment hole 22b and the alignment shaft 35 is set to be smaller than the clearance between the support hole 22c and the intermediate shaft 30. The pressure roller 22 can be displaced in all radial directions of the intermediate shaft 30 with respect to the thrust plate 33 within a range in which the alignment shaft 35 can be relatively displaced in each alignment hole 22b. When the roller 22 is displaced in an arbitrary radial direction, the center of revolution of the planetary rollers 20 to 20 is aligned, and processing errors and assembly errors of the constituent members are absorbed, thereby ensuring a uniform and smooth pressure contact state. It has come to be.
In the present embodiment, an annular elastic member 36 is interposed in the clearance between each aligning shaft 35 and the aligning hole 22b. Due to the urging force of the elastic member 36, each alignment shaft 35 is held at the center position of the alignment hole 22b.
The pressing roller 22 rotates around the axis of the intermediate shaft 30 by the revolution of the planetary rollers 20 to 20 (rotation of the holder 24), and each alignment shaft 35 comes into contact with the end of the alignment hole 22b. The roller 22 and the thrust plate 33 are integrated with respect to the rotation around the axis of the intermediate shaft 30 to transmit the rotational force. In this way, the thrust generating portion 25 is divided into two on the upstream side and downstream side of the rotational force transmission path, and the upstream pressing roller 22 is displaced in the radial direction of the intermediate shaft 30 with respect to the downstream thrust plate 33. The thrust generating unit 25 is provided with a centering function that allows center misalignment between the members constituting the continuously variable transmission mechanism 7 and apparently aligns. It is provided in place of the transmission ring 26.

Between the thrust plate 33 and the fixed plate 32, there is a cam mechanism 40 that displaces the thrust plate 33 in the axially separated direction with respect to the fixed plate 32 when torque or rotational force is generated between the plates 32, 33. Intervened. As shown in FIG. 2, the cam mechanism 40 includes four steel balls 41 to 41 provided on the front surface of the thrust plate 33 and the rear surface of the fixed plate 32 facing the cam grooves 33a. It has a structure sandwiched between the provided cam grooves 32a. The four steel balls 41 to 41 are held by the holding plate 42 at the quarter positions around the axis of the intermediate shaft 30.
As shown in FIGS. 5 and 6, the cam grooves 33 a to 33 a on the thrust plate 33 side and the cam grooves 32 a to 32 a on the fixed plate 32 side are circumferential with the same diameter with respect to the axis of the intermediate shaft 30. Opposite the upper quadrant position. The cam grooves 33a to 33a and 32a to 32a of both the plates 33 and 32 are formed in groove portions that are gradually different in depth in the rotation direction (the direction indicated by the white arrow in FIG. 6). One steel ball 41 is sandwiched between the cam grooves 33a and 32a facing each other.
For this reason, the rotational force applied to the thrust generating portion 25 acts between the thrust plate 33 and the fixed plate 32, thereby generating a relative displacement in the rotational direction between the plates 33 and 32. Then, coupled with the elastic deformation of the transmission ring 26, the steel ball 41 rides on the inclined surfaces in the rotational direction of the cam grooves 33 a, 32 a, so that a part of the rotational force (axial component force) pushes the thrust plate 32 to the pressing roller 22. The axial force acts as a pressing force, and therefore this axial force acts as a pressing force for pressing the pressing roller 22 against the planetary rollers 20 to 20 in proportion to the rotational force. As described above, according to the thrust generating unit 25, the thrust plate 33 and the fixed plate are used as thrusts for uniformly pressing (three-point press contact) the sun roller 21, the pressing roller 22, and the transmission ring 26 to the planetary rollers 20 to 20. 32 is configured to generate an urging force of the compression spring 34 interposed between them and an axial force of the cam mechanism 40. Moreover, the thrust generating unit 25 is configured to transmit the rotational force to the intermediate shaft 30 through the path from the pressing roller 22 to the fixed plate 32 while generating the thrust as described above.

In this three-point pressure contact state, when each planetary roller 20 rotates around its axis by the rotation of the sun roller 21 when the drive motor 6 is started, the planetary roller is connected via the pressure contact state of each planetary roller 20 to the transmission ring 26. 20 to 20 revolve around the intermediate shaft 30. As the planetary rollers 20 to 20 supported by the holder 24 revolve around the intermediate shaft 30, the pressing roller 22 rotates integrally. When the pressing roller 22 is rotated, the thrust plate 33 is rotated integrally by the engagement of the alignment shafts 35 to 35 with the alignment holes 22b to 22b. Therefore, the fixing plate 32 is rotated integrally via the cam mechanism 40, and consequently The intermediate shaft 30 rotates integrally. Thus, the rotational force of the drive motor 6 is transmitted to the intermediate shaft 30 via the continuously variable transmission mechanism 7.
When the intermediate shaft 30 after the speed change by the continuously variable transmission mechanism 7 rotates, the rotational force is further changed at a constant reduction ratio via the gear transmission mechanism 8 and transmitted to the spindle 9, and thus the tip tool rotates.
When the transmission ring 26 of the continuously variable transmission mechanism 7 is positioned on the small diameter side of the planetary rollers 20 to 20 in the transmission state of the rotational force that rotates the spindle 9 and the tip tool, the reduction ratio of the continuously variable transmission mechanism 7 is small. Thus, the spindle 9 rotates at a high speed. When the transmission ring 26 is displaced to the larger diameter side of the planetary rollers 20 to 20, the reduction ratio of the continuously variable transmission mechanism 7 is increased and the spindle 9 rotates at a low speed.
As described above, the transmission ring 26 is fixed along the inner peripheral side of the ring holder 27. The ring holder 27 is displaced in the axial direction by a rotation operation of the operation ring 45 provided in the main body housing 5. Due to the displacement of the ring holder 27 in the axial direction, the transmission ring 26 is displaced between the small diameter side and the large diameter side with respect to the conical surface 20a of the planetary roller 20, and thereby the rotational force of the drive motor 6 is stepless. And is transmitted to the intermediate shaft 30 and then output to the spindle 9 via the gear transmission mechanism 8.
As described above, the aligning function of the continuously variable transmission mechanism 7 is also provided in the thrust generating unit 25. For this reason, as described above, the transmission ring 26 is supported so as to be displaceable only in the axial direction of the intermediate shaft 30 and does not have a conventional alignment function. It is greatly simplified compared to

According to the power tool 1 of the present embodiment configured as described above, in the continuously variable transmission mechanism 7, the centering action of the planetary rollers 20 to 20 is performed by the thrust generating unit 25, and the transmission ring 26 is a conventional one. Unlike the intermediate shaft 30, the intermediate shaft 30 is supported so as to be displaceable only in the axial direction. For this reason, a member or a space for supporting the transmission ring 26 so as to be displaceable in the direction perpendicular to the axis is not required, and the support structure can be greatly simplified as compared with the conventional structure. Can be made compact in the radial direction (the direction perpendicular to the axis of the transmission ring 26).
In the present embodiment, the alignment function between the constituent members constituting the continuously variable transmission mechanism 7 such as the alignment operation of the planetary rollers 20 to 20 is performed by the pressing roller on the upstream side of the power transmission path in the thrust generating unit 25. 22 is displaced in the direction perpendicular to the axis of the transmission ring 26 with respect to the thrust plate 33 on the downstream side. The upstream pressure roller 22 can be displaced (aligned) in the radial direction with respect to the thrust plate 33 within a range in which the alignment shaft 35 can be displaced in each alignment hole 22b.
In this embodiment, the elastic member 36 is interposed in the clearance between each alignment hole 22b and the alignment shaft 35, and each alignment shaft 35 is brought to the center position of the alignment hole 22b by the biasing force. It is designed to be held (centered). For this reason, when the thrust generating unit 25 is assembled, the pressing roller 22 and the thrust plate 33 can be assembled in a substantially concentric state, so that the thrust generating unit 25 can be easily assembled.

Various modifications can be made to the embodiment described above. For example, although the configuration including the gear transmission mechanism 8 in addition to the continuously variable transmission mechanism 7 has been illustrated, the gear meshing transmission mechanism 8 may be omitted.
Moreover, in the thrust generation part 25, although the structure which interposed the elastic member 36 between each alignment shaft 35 and the alignment hole 22b was illustrated, the elastic member 36 which concerns may be abbreviate | omitted.
Furthermore, although the configuration in which the cam mechanism 40 is interposed between the fixed plate 32 and the thrust plate 33 is illustrated, this can be omitted. In such a case, the sun roller 21, the transmission ring 26 and the pressing roller 22 are pressed against each planetary roller 20 mainly by the urging force of the compression spring 34.
In addition, the configuration in which the alignment shafts 35 to 35 are provided in the thrust plate 33 on the downstream side of the power transmission path and the alignment hole 22b is provided in the upstream pressure roller 22 is illustrated. It is good also as a structure which provides a mandrel and provides alignment holes in the thrust plate 33.
In addition, although a rechargeable driver drill is illustrated as the power tool 1, it is an air tool that uses an air motor instead of an electric motor as a driving source, such as a disk grinder or a cutting machine, or a traction drive type The same applies to the case where a step transmission mechanism is provided. Furthermore, the present invention can also be applied to a power tool that uses an internal combustion engine (engine) as a power source.

1 ... Power tool (rechargeable drill driver)
2 ... Tool body 3 ... Handle 4 ... Battery pack 5 ... Main body housing 6 ... Drive motor 6a ... Output shaft 7 ... Stepless transmission mechanism (traction drive mechanism)
8. Gear transmission mechanism (planetary gear train)
8a ... planetary gear, 8b ... carrier, 8c ... internal gear 9 ... spindle 10 ... chuck 11 ... switch lever 12, 13 ... bearing 20 ... planetary roller, 20a ... conical surface 21 ... sun roller 22 ... pressure roller, 22a ... boss Part 22b ... alignment hole 22c ... support hole 24 ... holder 25 ... thrust generating part 26 ... transmission ring 27 ... ring holders 28 and 29 ... bearing 30 ... intermediate shaft, 30a ... gear part 31 ... bearing 32 ... fixing plate, 32a ... cam groove 33 ... thrust plate, 33a ... cam groove 34 ... compression spring 35 ... alignment shaft 36 ... elastic member 40 ... cam mechanism 41 ... steel ball

Claims (9)

It is a power tool equipped with a continuously variable transmission mechanism that continuously changes the rotational output of the drive motor and outputs it to the spindle to which the tip tool is attached,
The continuously variable transmission mechanism includes a sun roller that is rotated by the drive motor, a plurality of conical planetary rollers supported around a holder, a transmission ring that inscribes a conical surface of the plurality of planetary rollers, A thrust generating section that transmits a rotational force to the spindle while generating a thrust force that presses a plurality of planetary rollers against the sun roller and the transmission ring; and the conical surface of the planetary roller by moving the transmission ring in an axial direction The rotational output of the drive motor is steplessly changed by changing the pressure contact position of the transmission ring between the small diameter side and the large diameter side and output to the spindle via the thrust generating unit. And
The thrust generating unit is a power tool provided with a centering function instead of the speed change ring provided so as to be displaceable in a direction perpendicular to the axis of the speed change ring and to transmit a rotational force. 2. The power tool according to claim 1, wherein the thrust generation unit is divided into an upstream side and a downstream side of a rotational force transmission path, and the upstream side can be displaced in a radial direction of the transmission ring with respect to the downstream side. Power tool provided in 3. The power tool according to claim 2, wherein the thrust generation unit is provided with a centering hole on one of an upstream side and a downstream side of the rotational force transmission path, a centering shaft is provided on the other side, and the centering shaft is A configuration in which a rotational force can be transmitted by being inserted into an alignment hole, and the upstream side is displaced with respect to the downstream side in the radial direction of the transmission ring to align the holder with the transmission ring; Power tool. 4. The power tool according to claim 3, wherein an elastic member is interposed between the aligning hole and the aligning shaft to center both of them. 5. The power tool according to claim 1, wherein the continuously variable transmission mechanism has a three-point pressure contact structure in which a pressing roller is pressed against the planetary roller in addition to the sun roller and the transmission ring. And the thrust generating portion includes the pressing roller so as to be displaceable in the radial direction of the transmission ring. The power tool according to any one of claims 1 to 5, wherein the thrust generation unit includes a fixed plate fixed to the spindle in an axial direction and a rotational direction, and a spindle in the axial direction and the rotational direction. A compression spring interposed between the thrust plate supported in a displaceable manner, and generating a pressure contact force between the sun roller and the transmission ring with respect to the plurality of planetary rollers by an urging force of the compression spring; A power tool configured to transmit a rotational force to the spindle. The power tool according to claim 6, wherein when a rotational force is generated between the fixed plate and the thrust plate, the thrust plate is displaced in a direction in which the thrust plate is axially separated from the fixed plate. A power tool with a cam mechanism. The power tool according to any one of claims 1 to 7, wherein the speed change ring is an inner periphery of a ring holder provided so as to be movable only in an axial direction of the spindle with respect to a housing of the power tool. Power tool fixed along. 9. The power tool according to claim 8, wherein the ring holder is supported on an inner peripheral side of an operation ring provided to be rotatable about the spindle axis with respect to the housing. A power tool configured to change the pressure contact position of the transmission ring with respect to the conical surfaces of the plurality of planetary rollers between a small diameter side and a large diameter side by displacing the ring holder in an axial direction by a rotation operation.

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